Aerial lifts are commonly mounted on wheeled vehicles such as trucks, trailers, etc. The conventional lifts normally comprise an extendable boom means which has one end pivotally and rotatably secured to the truck so that the personnel bucket which is pivoted to the other end of the boom means may be positioned at the desired work level. The personnel buckets are normally pivotally secured about a horizontal axis to the end of the boom means. The position of the bucket is ordinarily controlled by a gravity level system with a hydraulic snubber or a disc brake apparatus. Thus, when the hydraulic snubber and disc brake are disengaged, the bucket is free to pivot relative to the boom. The hydraulic snubbers and disc brakes are normally disengaged as the boom is being manueuvered and such free pivotal movement between the boom and the bucket can result in injury to the person in the bucket. Additionally, the weight of the bucket and the person therein is not always balanced so that the bucket is tilted when the bucket reaches the desired work level and such an attitude creates a dangerous situation.
Therefore, it is a principal object of the invention to provide an aerial personnel lift which includes means for automatically positioning and maintaining the personnel bucket in a vertical position.
A further object of the invention is to provide an aerial lift which includes an electrical screw-motor pivotally secured to and extending between the boom and the bucket to maintain the bucket in the desired position regardless of the vertical position of the boom.
A still further object of the invention is to provide an aerial lift which is economical to manufacture, durable in use, safe to operate and refined in appearance.
These and other objects will be apparent to those skilled in the art.